Echinococcosis: antibodies to the echinococcus in the blood

Antibodies to echinococcus in serum are normal.

Echinococcosis (syn: echinococcus granulosis, cysticercus polymorphus, etc.). Skin is affected in 8% of cases. In the subcutaneous fat layer, cysts develop in the form of tumor-like formations, gradually increasing in diameter to 5-6 cm or more, a hemispherical shape, a dense elastic consistency, fluctuating, transmissive in transmitted light. If echinococcus perishes, the contents of the cyst are subjected to caseous necrosis, calcified. Sometimes, with the addition of a secondary infection, abscesses and ulceration are formed. Urticaria rashes can be observed.

Pathomorphology. In the skin of a person, changes of the cysticercic type are typical: in the dermis there are many blisters, in the lower part there is a dense leukocyte infiltrate, in which there is a racemous cavity filled with a large number of hydatids oval or ribbon-shaped with small hyperchromic nuclei. Among them, sometimes it is possible to see a scolex (head), around which reactive inflammation develops with the presence of multinucleated giant cells. In the future, the cellular strands of echinococcus are torn, subjected to necrosis, impregnated with calcium salts and encapsulated.

Echinococcosis, tissue helminthiasis caused by larval stages of Echinococcus granulosus or Echinococcus multilocularis. In humans, Echinococcus granulosus causes the formation of single-cell cysts, mainly in the liver and lungs (hydatidic echinococcosis), while Echinococcus multilocularis - the formation of multi-chamber (alveolar) lesions (multi-chamber echinococcosis), capable of invasive growth in adjacent tissues. Diagnosis of the disease presents certain difficulties. Eosinophilia is noted in less than 25% of cases.

To diagnose echinococcosis, serological diagnostic methods have been developed: RPGA, RSK, latex agglutination reaction with antigen from the fluid of echinococcal blisters and ELISA.

The EIA method is most effective for the diagnosis of echinococcosis. However, the use of this method is limited by the fact that many carriers of echinococcal cysts do not develop an immune response, antibodies in the blood are not formed. ELISA gives positive results in 90% of patients with cysts in the liver and only in 50-60% of patients with lung disease. High antibody titers (above 1: 400) have a sensitivity of 90% and a specificity of less than 100% in cases with daughter cysts in the liver and peritoneum; 60% of the sensitivity - when the lungs and bones are affected; 10% - false-positive results (cysticercosis, collagenoses, malignant neoplasms). After surgical removal of cysts, the detection of antibodies to serum Echinococcus is used to monitor the radicality of the operation performed. The disappearance of antibodies 2-3 months after the operation indicates a radical cyst removal, a decrease in antibody titer and subsequent growth in the postoperative period - a relapse of the cyst. In some cases, after successful surgical treatment, elevated titers can last for years. The maximum detectability of echinococcosis by ELISA method (up to 98%) was noted when echinococcal blisters of live parasite were located in the liver, abdominal cavity and retroperitoneal space, as well as in multiple and combined lesions. With lung lesions, as well as in the presence of one to three cysts of a small (up to 2 cm) size, the serological diagnostic efficiency is lower and varies between 70-80%. The least informative method is ELISA for echinococcosis of the nervous (dorsal or brain, eye), muscle or bone tissue, as well as for the dead and calcified parasite (sensitivity does not exceed 40%). High antibody titers can be in patients with an active process, more often localized in the organs of the abdominal cavity. In the case of pulmonary localization of echinococcus cysts (even in the presence of large cysts), antibody titers may be low.

Low titers of antibodies to echinococcus can be detected in the early period of the disease (cysts up to 2 cm in diameter), as well as larvocysts in calcified shells; a sharp decrease in titers is possible with a far-reaching process, in the late, inoperable stage of echinococcosis.

With the use of serological methods for diagnosing echinococcosis, false positive results are possible when there are nonspecific antibodies in the blood that are similar in structure to antibodies to echinococcus. The most often false positive results are found in somatic and infectious diseases, accompanied by extensive destructive processes in the affected organs (cirrhosis of the liver, pulmonary tuberculosis and other tissues, oncological diseases). False positive reactions are possible with other helminthiases (for example, opisthorchiasis, fascioliasis and cysticercosis).

Serological studies are used for primary diagnosis of echinococcosis, evaluation of the results of operative and conservative treatment and monitoring of patients in the dynamics, as well as for the early detection of recurrences of the disease. Localization and viability of larvocyst of echinococcus hydatidid and alveolar, the intensity of invasion, as well as the state of the host's immune system, affect the intensity of antibody formation and the detection of invasives with the help of serological reactions.

Indications for the appointment of serological tests:

• presence of volumetric education or cysts in the liver and other organs;
• epidemiologically significant contingents are persons classified as at risk (hunters and their families, zootechnicians, shepherds and shepherds, leather workers etc.), as well as those living in foci of echinococcosis.

[1], [2], [3], [4], [5], [6], [7], [8],